# After latest April 2026 update to Ubuntu 24.04 LTS, thumbnails are no longer being generated

> Source: <https://gist.github.com/andrewpayne68/1be45afa51977d5a91d51c69eafb9764>
> Published: 2026-04-24 11:00:59+00:00

Steps to fix it:
Relax the security restriction (immediate fix): Open your terminal and run:
sudo sysctl -w kernel.apparmor_restrict_unprivileged_userns=0
Clear the "failed" thumbnail cache: This forces Nautilus to retry generating thumbnails for files that previously failed:
rm -rf ~/.cache/thumbnails/fail/*
Restart the file manager: Close all Nautilus instances to apply the changes:
nautilus -q
Single Line Command:
sudo sysctl -w kernel.apparmor_restrict_unprivileged_userns=0 && rm -rf ~/.cache/thumbnails/fail/* && nautilus -q